Wire stand forming machines are well known in the prior art for use in twisting or stranding two or more individual strands of wire together to form wire cord or other stranded wire products. One such machine commonly used in producing small sized stranded wire products, referred to as a "wire buncher", accepts two or more individual wire spools mounted onto a stationary creel between a pair of rotating discs or arms, each having a pulley, or "flying sheave" at its periphery. The individual strands of wire are pulled through an orifice at the axis of one rotating arm and radially outward over the flying sheave thereon, while the flying sheave rotates around the orifice. Each such rotation serves to put one full twist into the wire bunch. The wire bunch then passes back to the other rotating flying sheave while revolving around the creel. The bunched wire then is pulled radially inward and through another orifice at the axis of rotation, and axially outward onto a take-up spool. This rotation about the second orifice serves to put another twist into the bunched wire before it is reeled onto the take-up spool.
Although such wire bunching machines have worked satisfactorily to produce many stranded wire products, some customers are demanding closer tolerances on quality of the product. For example, steel wire cords used in the production of steel belted tires must be produced to very close tension requirements. Because of the way the several individual spools of wire on a wire buncher are mounted, it is not always possible to assure that the individual strands of wire are subject to the same tension with respect to each other during unwinding. In addition, it is not possible to maintain a constant tension in an individual strand of wire from commencement to finishing of the unwinding. Since most wire bunching machines utilize some sort of brake system which applies a constant pressure on the wire spools to effect tension in the wire, it is clear that the resulting wire tension will increase as a spool progresses from full to near empty. That is to say, the unwinding torque is greatest when the spool is full and decreases as the amount of wire removing on the spool decreases. This is due, of course, on the decreasing moment, i.e. decreasing radius from the axis of rotation to the point of tangency where the wire is pulled from the reel. With the diminishing torque there is a corresponding increase in tension in the wire. Hence, in applying a constant frictional pressure on the wire spools, the bunching tension increases progressively as the wire spools progress from full to near empty.
Various attempts to overcome the above problems have resulted in spool mounting arrangements and brake systems which have substantially enhanced the hardware mounted on the creel. This in turn has necessitated a wider spacing between the flying sheaves and/or a greater radius of rotation thereof, either of which is most detrimental. Specifically, increasing the radius of rotation on the flying sheave spacing necessitates a slower operating speed. Firstly, the centrifugal forces on the length of stranded wire spaced between the flying sheaves increases as the cube of the distance between the flying sheaves. Secondly, these centrifugal forces increases proportionally with increases in the radius of rotation of the flying sheaves. Accordingly, maximum operating speed can be effected by minimizing the radius of rotation and particularly minimizing the flying sheave spacing.